If my herniated disc is not pressing on a nerve root, could it still cause my low back pain and leg pain?

Although controversial, it is possible. A herniated disc is felt to cause lower extremity or radicular pain by potentially two different mechanisms. The most obvious is by physical or mechanical pressure on the nerve root. The second is by a chemical irritant and/or acid \ base changes due to the contents of the inner part of a disc reaching the nerve root through a herniation or even a simple fissure through the disc. The end result of both mechanisms is inflammation and irritation of the nerve root, which goes down your leg.